Electric heating-core for smoothing-irons



(No Model.) 2 Sheets-Sheet 1.

W. MITCHELL. l ELECTRIC HEATING GORE FOR SMOOTHING IRONS.

Patented Oct. I3, 1891'.

lNvENToR WITNESSES s venus co., mow-urna., wsu

2 She W. TCHELL. ELECTRIC HEATIN RE POR SMOOTHING IRONS.

SI1 8 C UNITED STATES PATENT OFFICE.

IVILLIS MITCHELL, OFVMALDEN, ASSIGNOR. T() THE BUTTERFIEIiD-MITCHELLELECTRIC HEATING COMPANY, OF BOSTON, MASSACHUSETTS.

ELECTRIC HEATING-CORE FOR SMOOTH'ING-IRONS.

SPECIFICATION forming part of Letters Patent No. 460,980, dated October13, 1891.

Application led March 24, 1891.

To all whom, t may concern:

Be it known that I, XVILLIs MITCHELL, a citizen ofthe United States,residing atl Malden, in the county of Middlesex and State ofMassachusetts, have invented certain new and useful Improvements inElectric Heating- Cores for Smoothing-Irons; and I do hereby declare thefollowing to be a full, clear, and exact description ot'the invention,such as Io will enable others skilled in the art to which it appertainsto make and use the same.

The chief object of this invention is to provide a new core for the wireof electric heaters which shall separate the cols or spi- Pals thereofabsolutely and insula e them from each other, while holding each in itsproper position. .2

To this end my invention consists, mainly,`\ in a block or solidpiece'ot soapstone or otherl 2o` insulating material in any suitableform,l1avfr ing grooves for the wire eut in its sides `or ends or both.This core is especially designed for use in bed-warmers, flat-irons,cylindrical smoothing devices, cooking utensils, and other smallarticles, but of course is not confined thereto.-

In the accompanying drawings, Figure l representsaperspective viewof myimproved core, having grooves in its sides and the heating-wire woundthereon, but partly broken away. Fig. 2 represents a similar View of ablock having grooves in its sides, but not in its ends, the wire beingwound endwise as well as crosswise, and broken away to show the grooves.Fig. 3 represents in perspective as a modification a cylindrical corehaving circumferential grooves. Fig. 4. representsa side elevation ot'the same with the wire wound thereon. Fig. 5 represents a perspectiveview of another modification, having a fiat form, with the wire wound ingrooves in its sides and partly broken away. resents a metallic shell,open at one end to receive this latter core and constituting with it anelectrically-heated griddle. Fig. 7 rep- Fig. S represents aheating-cylinas determined by experiment.

ience both ends ot the Wire leave the core or Fig. 6 repi Serial No.386,204. (No model.)

der constructed as in Fig. 3 and coated with pulverized soapstone andasbestus; and Fig.

f) represents a hollow {lat-iron body adapted to receive a modified formof core, also shown in said figure.

' In the said drawings, A designates the heating-wire which forms part'ot an electric circuit, and B the core on which it is wound. This coreis preferably of soapstone, but may 6o be of any other solid insulatingmaterial. As shown in Fig. l, a continuous helical groove B is made inits sides to receive the wire, said groove being of suflicient depth tohold the wire spirals in their proper position and the interval betweenone spiral of the groove and the next on either side being such as toinsure the best heating action ot the electric current passing throughthe wire,

For Couven-7o block at thc same end, one end ot' the wire passingthereto through a short oblique inner passage c from the nearer grooveand the other end of the wire being passed through 7 5 a longitudinalinner passage CZ, extending from end to end ot the said core or block.This construction is repeated in Fig. 5, except that the groove isbroken into a number ot parallel grooves, occupying the same posi- .8otion, by the ungrooved edges ot the flattened core, these being toonarrow to need grooving. The form shown in Figs. 3 andhas the continuousgroove ot Fig. l, and also the passages c d, arranged correspondingly tothose S5 above described, the chief difference being that the core inthe one case is a rectangular cubical ligure, whereas in the other it iscylindrical. This cylindrical core has gudgeons c screwed into its ends,they being available 9o for suspending it under car-seats or suspend-/i'ng it in bearings on standards D, as shown in Fig. S. A coating C otmingled asbestus and pulverized soapstone is given to it, as

`shownin this latter iigure, and becomes as 9`5 har/d as the coreitself, practically embedding the Wire therein and hiding it. To applythis coating mix together approximately equal parts of pulverizedasbestus and pulver-ized soapstone, with enough of any adhesive marooterial to form a paste or mortar. Then heat the soapstone core by theelectrical current.

'Then turn oftl the' said current and spread the aforesaid mixture onthe said heated core. The heat will cause it to harden, forming thedesired coating; or, as shown in Fig. 7, a heating-core having one ofthe forms above described may be heavily painted over and used as abed-warmer or foot-warmer or forany other heating purpose. It ispreferably provided with a handle E; or, as shown in Fig. 6, a fiathollow case F, having one end fopen, may receive the fiat form of coreshown in Fig. 5 and be used with it as an electric griddle. Legs g areprovided, giving this article a table-like appearance.

As shown in Fig. 2, a block of the form shown in Fig. l may be groovedspirally endwise as well as around its sides. The grooves of each setcut through those of the other set, so that neither is strictlycontinuous. The lengthwise grooves o are deeper than the grooves h toavoid contact of the coils of wire with each other and consequentshort-circuiting. I wind the wire first in the lengthwise grooves o andthen back on the sides of the block or core in the grooves l) to the endof the block Where the winding began. A short passage m from the lastlengthwise groove o on the right to the nearest crosswise groove l)extends through one corner of the block and allows-this transfer of thewire from one set of grooves to the other, the direction of winding, asin the other figures, being indicated by arrows.

Heating-cores constructed as hereinbefore described are capable of beingused in a great variety of ways and with many kinds of covering orincasement. A few of these have herein been explained and illustrated;but such a core, wherever used, is a part of my invention. It dispenseswith all other insulation and holds the wire absolutely in its positionand arrangement of greatest efficiency.

Of course the core may have the same grooved construction without beingmadeof insulating material and will answer well if the Wire is coated.The grooves are arranged to hold each spiral of the wire in a space orinterval about ten or twelve times its own width, varying more or lessaccording to the work to be done.

Any form of core shown may of course be coated like the cylinder shownin Fig. 8, or painted like the bed-warmer shown in Fig. 7, or put into ahollow casing, as suggested by the hollow griddle-shell in Fig. (i orthe fiatiron body of Fig. 9, which last receives a core of the formshown also in said ligure. This receso core is' rounded at the iippeivcorner' of oneJ1 end to' tit the end of the cavity in the shell;Otherwise it has substantially the construction shown in Fig. 1.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

l. In combination with a wire forming part of an electric circuit andwound in a heating coil or spiral, a solid core of insulating materialwhich is grooved to receive the said wire and provided with a passagepermitting the return of the wire to the end of the core where thewinding began, substantially as set forth.

2. In combination with a wire forming part of an electric circuit, acore or block which is provided with a set of spiral grooves runningcrosswise anda similar set running lengthwise, the wire being woundfirst in one set of grooves and then in the other, for the purpose setforth.

3. In combination with a wire forming part of an electric circuit, acore which is provided with a set of grooves running crosswise and a setrunning lengthwise of the said block, one set of grooves being deeperthan the other set, and the said wire'being wound first in the deepergrooves and afterward in the shallower ones, substantially as set forth.

4:. In combination with a wire forming part of an electric circuit, anda grooved core ou which it is wound, a coating of powdered soapstone andasbestus for the outside of the said core and wire, substantially as setforth.

5. In an electrically-heated utensil, the combination of a non-metallicbar or core inclosed within the body of it, and a wire forniing part ofan electric circuit, which is wound on said core, each spiral-of thewire being in a space or interval about ten ortwelve times its ownwidth, more or less, according to the work to be done, substantially asset forth.

6. A grooved core, in combination with a wire wound thereon in -thegroove or grooves thereof and forming part of an electric circuit, thesaid core being provided withv a pas sage through a part of it for oneend of the said wire to extend outward from the grooves through one endof the said core, substantially as and for the purpose set forth.

In testimony whereof I affix my signature in presence of two witnesses.

WILLIS MITCHELL. Witnesses:

ARTHUR B. SMITH, WILLIAM P. CUTLER.

IOO

